function [mean mymin mymax n] = f11 (x)                              %  f11.m
  fprintf('%s: no of inputs %2d ,  no of outputs %2d\n',mfilename,nargin,nargout);
  msg=nargchk(1,1,nargin,'string');  
  if length(msg) ~=0
      warning(msg);
      fprintf('%s: default input set to [33 55 11] \n',mfilename);
      x=[33 55 11];
  end
  error(nargoutchk(0,4,nargout));  
  n=length(x); mean=sum(x)/n; mymin=min(x);mymax=max(x);
end
